Machine tool



Oct. 21, 1952 F. PoLK ETAL 2,614,368

' MACHINE TooL Filed May 6, 1948 f Y 4 Sheets-Sheet 1 4 Sheets-Sheet 2 MACHINE TOOL L. F. POLK l' AL Oct. 21, 1952 Filed May e. 1948 INVENTOR5 BY Miam v Oct. 21, 1952 L. F. PoLK ETAL MACHINE TOOL 4 Sheets-Sheet 3 Filed May 6, 1948 K VIII/ l In',

' INVENTOR 'BY.,M2%2

Oct. 21, 1952 F. PoLK ETAL MACHINE TOOL 4 Sheets-Sheet 4 Filed May 6, 1948 INVENTORJ Patented Oct. 21, 1952 MACHINE 'root Louis F. Poikand Willis Fay Aller, Dayton, Ohio,

assignors to The Sheiield Corporation, Dayton, Ohio, a corporation of @hic Application May 6, 1948, Serial No. 25,446

it claims. l

This invention relates to prole grinding machines and to a method and means to facilitate precise grinding oi' a desired contour on the workpiece.

One object of the invention isthe provision of a prole grinding machine having an optical projector for producing an enlarged surface pron jection of the workpiece of such character that vthe physical characteristics of the surface' are clearly apparent on the projection screen and making a burnin the work instantly observable.

Another Objectis the provision of a profile grinding machine of the character mentioned in which a dark image of the grinding wheel is produced on a readily observable projection screen and in which the observable projections of the grinding wheel and the work are clearly distinguished from one another by the brilliant 'light .color appearance of the work projection.

Another object resides in the method of opaque projection in which two converging beams of light are directed on the work to Abe viewed so that the beamsare in a common plane transverse of the direction of parallel scratches given to the work surface so that a brilliant detail revealing projection of the Work surface results, as viewed from a direction between the illuminating beams.

Another object is the method of imparting a desired profile to a part, in which a suriace of the part is given ya series of generally parallel scratches and an enlarged surface projection of the scratched surface and a projection of the grinding wheel, on an enlarged scale, is produced on a projection screen with the work projection vof a brilliant character as compared withk the darker image of the grinding wheel, so that the workfcan be ground precisely to a desired .profile by relative adjustments of the grinding wheel and the work while viewing the enlarged -pron v jection and comparing it with a desired guide line on the projection screen.

Another object is the provision of a contour grinding machine having means conveniently accessible to the operators location for precisely controlling the movementsof 'the tool supporting slides.

Another object is the provision of a proling machine having tool and -work holders relatively adjustable and in which precise adjustment of one of the holders is obtained by a fluid-filled 2 n y holder and the other of which is manually controlled by an adjusting device that may be moved, as. desired, for coarse adjustment purposes-- Other objects and advantages. of the invention will be apparent from the following description, the appended claims and the accompanying drawings, in which, Fig. 1 is a perspective View of a profilegrinding machine embodying the present invention; Fig. 2 is a vertical section through the middle of the tool holder taken in a plane `extending towards the tool holder;

Fig. 3 is a vertical section on the line 3.--3jof Fig. 2 with the central portion of the gure shown in elevation;

Fig. 4 is a front elevation of the two nne Ladjustment controls, one of which is shown in vertical section; i .1,

Fig. 5 is a side elevation of the machine on a reduced scale, showing the optical projection system;

Fig. 6 is a front elevation corresponding Fg- 5; Y v 1.

Fig. '7 is a detail view on an enlargedscale showing the character of the projection obtained on the viewing screen; and I Fig. 8 is av view of the upper surface of workpiece.

In the drawing, in'which the same reference numerals are applied to like parts in the several views, the preferred form 'of the invention has been illustrated in its embodiment Y in-` an optical proiile grinder having .an opticalprojection device that provides an enlarged :surface projection of the work. In this embodiment, the machine tool comprising a main frameV I0 having a horizontal work supporting tablegll arranged for horizontal adjustment on astandard I2 that is vertically adjustable by anyv suitable means under the manual control Yofthe operatorso that the work can be located at the proper height and position for profiling. The workpiece itself may be clamped on thetable by means of suitable holding screws I3 and a the ' holder clamp I4 applied to the upperA surface of the work.

Arranged on the main frame ES at oneside of the work table is a tool holder generally designated I5 and carrying a grinding wheel I6 driven by an electric motor ll' through a belt I8 or other suitable driving mechanism which also causes vertical reciprocating movement of the grinding wheel. on the holder I5. Theftool holder-I5. is `arranged on slides and turn table as shown. in Figs. 1, 2 and 3, so that the grinding.v wheel can be moved towards or away from the work holder and also along the edge of the work and also permitting the axis of rotation of the grinding Wheel to be moved by adjusting the tool holder about a Vertical axis in order that any desired movement may be given to the grinding wheel. Thus the wheel holder I5 is held for rotatable adjustment about -a vertical axis on an upper slide 2``0"by means of suitable holding clamps 2l in engagement with an annular groove in the lower side of the wheel holder and operativelto clamp the wheel holder down on the top4 ofthe slide 29 when the Wedge blocks 22 are drawn towards one another in clamping `engagement with cam surfaces 23 on the holders '-2l. `4The wedge blocks 22 are internally threaded, *one right hand and one left hand,: and engaged by:.a rotatable shaft 24 that can be operated by the hand knob 25. The slide is carried Abytwo guided bars 2B and 2'1 the ends of which. are Zxedzltor depending zendanges 2'8 .randZ 9 :on the s'lide. Y.The middle :portions of .these .bars rare mounted)Y for fendwisexmovement in lanti-friction "bearing :members 2:30 ."carr-ied by .upward-1y ,projectingfwal'ls-B I of ratdrum 32 which is heldJ for trotatable ta'djustment #about a s-vertical .faxis on the top of a lower slide .33.` :Holdingclam-ps simi- -larl-tothefclamp; 21 `operateinian:annular-groove 5321shown1in1.Fig.::2. The toolxholder 4can move onthefislide333m aatdirectiontowards fandfrom -theioperator, Acorresponding `to the fdi'recti'on of the grinding wheel axis fin the fpositionof the parts illustrated.

Theislidei is movable .in .fa direction; towards and .from the work holder on the drum-34zhaving canti'C-l'frietion tbearing :members 35 fsupporting fixed to depending flanges 31 on thesrslide133. vL'Ih'efdrnm 34i-is..rotatableiabout. its :own `axis on thel'base platel 38f.-which.is;held '.inxedposition on the main frame IB. A lock bar 39 operated by Sal-leven40.icansbeftnrneditorclamp the drum34 to plate 38 or to release the drum so it caniibe 'fturned'ibyfhand-onithezplate to :properly arrange '-theliplaneoffrotationofitheigrindingfwheel. :The bar 39 has an eccentric portion'dflrwhich-presses down oni'agclamp .'bar'42' thuspulling-downwardly on the bolts 43 the upper ends of lwhich rare :adaptedforliengagement in the-.grooVe-AA in the :.drum'34.

"iTheLmeans'for.;'operating `the upper slide i211)` .on 'itheA loweris'ide rfandfor 4operating fthe lower sside ron'thelibase of itheframe, :to ,controlzthe .vmove- .'.r'm'ents :of zthe izgrnding"wheelr..in a Aplurality lof :a'ngularly related directions .lduring grinding, comprises:afluidsystemiof `.constant capacityi for eaichrnrlthe -slides, "with individual control velem'entsr oripistons.1arran'ged:fadjacent Ione `another :in alposition:convenientixo'` the :operator standing Coarse` or :rapid tadljustments 1ofthe1two-2slides 2 arev also :provided so Tlthattheslides Lean tbe *..individually .moved `quite rapidly to 1 bring them; into '.approxirnate operation position. .Thuslas shownmore `particularly .in.f;l=?ig..2, 'ltheisli'de S331 has Ta passagef-d 6 closed at its outer end by cover plate 41 and forrning a Yohamb'er thatzreceivesiapiston llhavingan imperforatepiston head i119. The fpistonll :is holi'lo'w, :as vwill be apparent, :and the end of .the

' i piston opposite theheadis guided inrand suitably ,.Lkeyedagainstzrotation 'within a .'cylinderbore in rilidef33. lThisportion'ofLtlie pistonis internally threadedfandzengaged' by an-adjusting screw 5l rotatablytcarriedfby'zbearings z52. and T53 iso ias to :causeren'dwise:movementizofzzthepiston y#l8r-when the screw is turned. The adjusting screw 5l can be rotated by a handle 54 applied to the outer end 55. Rotation of the screw 5| thus moves the piston 48 in an axial direction so that with 5 liquid filling the cylinder space to the right of the piston and flow into or out of that space prevented, the piston 48 and the slide 33 will move as .rra-unit. fMovement of the piston'towards the `right asviewed'in Fig. 2"un`der such conditions will carry the slide 33 with it since the liquid within the chamber 46 cannot be compressed, while movement of the piston towards the left will be followed by the slide 33 due to the action lof a compressionspring 5'1 interposed between ia shoulder fQSSon'Fthe piston and a shoulder 59 onthefsl-ide. "ift-should be noted that the spring :.acts'rtdyieldingiy move the slide in a direction away from the workpiece so that should any y'lea-ka-'geHobtain in the uid system tending to decrease the space between the end of the piston .and theeen'd tcapft'l lonz-ithe i slide, '.zthenxtheragrind- .'ingwvheel :instead '.of being rmoved .towards the work and possibly :causing damage would :be moved away from the work.

.The chamber Mi i formed by the intertting. piston'fand; cylinder elements justvdescribedgis'. con- '.nected :by means vof .fa pipe lor a'condnitt 'rextending ato 'al controlrmeans 4,locateds'fadj acent .the --operators position :atstheifront fof thework table. Thisrcontrol'comprisesacontrolirknobl mounted on :azslrort .fshaft 5:62 that A iis frotatable within a bushing .'63 secured a mounting ,ab-look B4. 'Fixed to :the f shaft 132 is an :adjustingscrew 65 `tlireadedn 'tra xed nut e36 :and rengaging'ifthe `upper Iiside .of 1ra 1 control fpiston a l. That *piston is fslidab'le in ra fcylinder :6B :in the fm'ounting "block, .The :connecting pipe l-0 extends tto a passage., in thez'end-walle placingatherchamber ibel'owzpiston 'l rin; free communication-With? the chamber #l5 andflpreyen'ting :loss iof from '1 the :..systerrr A uspring 169 yiel'dinglyxholds fthe zcontrol=piston 6121110 against .thezfadjustingzscrew ;65 :but by turning the iadjnstmentflknob 6l :the pistonlzmay :be :raised or l.'lovizered..v so las :toi-cause 'uid'ito flow in :one directioncor Sthefotherabev tweenithe `opposite 'ends of the-'.*closediffii-iid. system. vrThe :diameter .Lof 'the lpiston 561'! Imay 1be much smaller than the diameter fofvthe --piston 48: so that a -very' .precise.- control of thelflocation ,oflthe slide :'33 :isfaifordedithe4 operator asf he Aad- Vjuststhefcontrol lknobl l1 While vcarefullyViewing thel imagefiof Itherworki on P the projection fscreen. The -slide`f2`0 :is-similarly adjustedon Jslide 33 v'alt11ou`gh1 the'`slide nmovements of-these -two slides are `90 .degrees apart. The parts vfor vadjusting "slide`20 :are 'given theffsame reference v"numerals withy a prime' mark, las fin-the -casefoff the parts for :slide *33. Thusvthelpistonr is AVsimilarly arranged for coarse yadjustrnentlcontrol byscrew '5l' movable by lever-*54' and operablelin bearings v52', T153. The chamber 116' in vslide -Z in which piston 43 operates is eonneotedby conduit "623' to another controlpistonoperated by vcontrol knob 'GIf adjacent =knobf`f5l. The two control rmembers-are preferably arranged on the worktable l l which normally does-not `mov-e -during the grinding operation so the operator-wi1l v-fknowexactly-where hef-may placehis fhan'ds on them. and -wli'ere1-they'-will 'be conveniently-acfcessiblef:withoutstretching:orr stooping.

Arranged in -.the iframe ylill, 1 as illustrated "in `.Figsi i5 andlfl 6,fis aeglass *'I-Oibelowtwhich is r`a. reector '37| 'i to Lproject s a Flight :beam: coming `from :ai .lamp T2 iverticallyzupwards along :the edgef of 75 .lthetworkpiece .F13 which is shown overhangingithe 5 v'side of the table Il. The light -that is not interjrupted bythe grinding wheel -or the work is rejlceivedvby-'the objective lens 'M focused on the work surface.

The light is reflected by a mirror l`'o'.rprism 15 so as to travel horizontally back away from the'operators position where it meets a reflector'ii'. It is then reflected successively from fmirrors 1l, i8 and 79 before it lmeets the rear side of the viewing screenv B where it gives an illuminated or light background and-provides *aL-darkshadow image 8| of the grinding wheel.

oftheworh-The projection screen, which may `vThe lens r,system is such that a suitable magnification is #provided so that the yprojection may be for example twenty-live `times the actual size ""b'e aground-'glass or translucent platejis providedf'vvithv lines such as the line 82 vthat shows a desiredcontour to be given to the workpiece,

lineZ-bei'ng either a solidline or a dash line as 'may' be desired. This line maybe applied to a substantially ltransparent or translucent sheet of paper fastened to the glass plate itself instead V:of Abeir'1g`fmade directly on the ground glass f screeni- The several mirrorsare carried in a housing 183 preferably of heavy sheet metal, 4fixed to the `A`.rear of the machine base IG at the back of the lbaserand extending upwardly to a point above '80 is 'above these holders at eye level, and faces ldirectly' towards the operator when he stands in .theltop of the tool and work holders. The screen normal-working position, providing a close, convenienti'gscreen location. A projecting top wall u'Sli forms asupp'ort for a drawl curtain 85 which `may'berdrawn back of the' operators head to f `c'ut 'off alarge'part of.v the room illumination.

. A desired illunfiinating system is provided for the uppersurfaceofthev workpiece so that a clear enlarged*surfacefprojection of the top, of the workpiece viszproduced on the projection screen.

This illuminating kmeans 'comprises av suitable vrlight source of high intensity'arrangedina llamp housingl S1; Land' providing Yltwo light beams through two parallel tubes 88, reflected by reflectors`88' and then traveling downwardly through L the `twoinclined tubes 89 to provide two downu 'wardly converging beamsxat opposite' sides of the gline of: sight oftheob'jectivelens ML Thesebeams converge to a common. area of illumination at the top ofthefwork surface and convergein a plane whichis transverse of the top of the work table and parallel to that edge of the work table i .which is overhung by the; side portion of the workpiece to be profiled.v The workpiece, before it is placed on the work table,- isfscr'atched. in a direction vtowards theedge'to; be proledv, as

showninliig, so as to be given a series of generally parallel scratchesasby rubbing it back and forth with emery cloth. While this` may Anot produce any change in the apparent character'of the work surface as viewed by the naked eye, it is an important step in fully utilizingthe advantages of the method and apparatus of the present invention, since the lightv beams directed -downwardly at an angle to the upper surface of the work and coming in aplane which is :transverse of the direction of the scratches on the upper surface ofA-thework, produces a bright orlight gray detail revealing surface projection o f the work, darker ofcourse than the illuminated background @but veryk much lighter than the shadow image of the grinding wheel.`v At thepoint of-intersection of the grinding wheel with the workgthere i; is no doubtat all as to'where thework begins and where the' 'wheel begins. 'this bruuant'uiumina- 6 tion of the workfsurface makes burns on the work instantly perceptible due to a darkening' of the 'work surface at the burned point so that if the operator should be moving the grinding wheel a little too fast and av burn starts to appear he can instantly reduce the speed of movement of the grinding wheel along the work or into the work.

Fig. '7 shows the characterof the enlarged projection on the viewing screen, in which the Very darkgray or black projection 8l of the grinding wheel is quite clearly distinguished from the much brighter light gray surface projection 9i! of the-work surface. The projection of the work surface, as shown in this figure, shows a portion r9i ground or contoured to coincide with the guide lines e2 on the screen, while a portion 92 remains to be cutvby the grinding wheel. The projections of the grinding wheel and of the -work are both clearly outlined since the background 93 is substantially white due to its illumination by the uninterrupted beam coming from the lamp l2. The projection of the grinding travel.

infront of the machine, control the fine adjustwheel is very dark 'because thev point on the grinding wheel viewed by the objective lens of the optical vsystem is out of focus, yet it is clearly outlined as the grinding wheel, during its up and down reciprocation, comes into actual contact with the work. The field representing the surface of the work is a bright, lightl gray' due to the reflection-of the light beams coming from the inclined light tubes '89. Some of this light is reiiected directlyupwardly normal to thel work surface as it strikes scratched portions ofthe work surface, since the scratches run normally to the vertical plane in which the light beams Thus the operator may,l while standing ments of the tool in a plurality of different directions, and indoing so he may have a clear direct viewl of the projection screen in front of him. If he should move the tool a little to fast so a vslight burn occurs, thatis instantly observable on the projection screen. Such would not be the casein thevconventional construction.

It is to be understood that the invention is not limited to the precise form of apparatus and the method herein described in connection with the kinvention in its preferred form, and that changes may be made therein without departing' from thescope of the invention as defined in the appended claims. v

Weclaim: `l. The method of opaque projection which comprisesv providing a hat surface that is'to be viewed with a series of closely adjacent generally parallel stratches running in one direction, directing two converging beams of light on the surface with the beams arranged in a substantially common plane substantially transverse of the direction of the scratches and substantially transverse of said surface sor that both beams strike the sur.-

v face at an angle 'substantially less than a right angle to provide an illuminated Zone, and making an ampliiied'opaque projection of the surface at the illuminated zone as Viewed from a direction perpendicular to the surface between the beams.

2. The method, in forming a predetermined shape on a side of a part having a flat surface generally transverse of that side, which comprises scratching the fiat surface in a direction towards y the saidside to be shaped to provide a scratched area of substantial size with closely Aadjacent scratches throughout said area, arranging' the part 1n a grinding machine, directing two con- .verging beams of vlight on the surface with the Tali :.beamsrarransed'finffazsubstantially .-ccmmon, plane ;,illuminated;zone on said scratched area,fmaking an iampli-ed I.opaque projection on .a viewing -Lscreenoofathefrsurface =at. the illuminated zone and .fat.rarzonepofi :grinding contact .as -viewed fromV a directionperpendicular.to the, surface between A:the beamsfgrindigngfthe .sideof the part to provide ;the :-predetermined f shape "by Y, relatively liadiusting; aggrifndigng-wheeliand ,the part-while .scomrparing.the..enlarged;projectionon thescreenf-with '*gude line onstheV screemhaving. the@ enlarged esiredrshape- '23. '.'Ilie .ff method in :forming a A. predetermined 1f-shape Qnutherside o appart havingaflatffsur-face generally transversegof.thatside which-comprises Scratching :the-flat :sur-face: Vina direction-towards the said: sidente-ibo 3 shaped .tog provide ,fan farea of substantial size :with f. closely f adjacent.- substan- ;-;tially parallel scratches throughout, arranging the part inca grinding machine, directing two 1.converging bea-ms of light ,onz theI surface with .thea-beams' arranged in ,a substantially common plane substantially.ttransvers yof `.said .surface so tha-tboth beams-#strike the surface at :the lgrindfgingfvzonezand in :said area at 1an angle. less'than ight-(angle, .f-directingf..another 'beam of .light :towards t the;1 grinding: zonesubstantially `perpeny'd icular to theflat surface-sand in a direction `vlsubstantiallygopposedv to the .direction of .the con- :verging beamssogthat the shadow of g afgrinding nfwheelsis i thrown. .on'laviewing screens making an gamplied-surfaceI projection on the viewing-screen y,iofthe ,said surface at the .zone of 'grinding .con- :tact as viewed-fromqaqdirection; perpendicular yto thesurfacmbetweenthe .converging .bea1 ns,` grindfi-:tlg thefside ofthe part :to-provide the predeterminedfshakpe :byz' relatively adjusting. thexgrinding iwheelfandthe part whilefcornparing .the v'enlarged projection .on the-screen with a guide line on-the screen-havingzthe. enlarged desired shape.

4, A grinding iemachine :comprising `a Tfr-ame havinggafworktable and a tool holder, adjustable Afmeansf operably interconnecting said tool :holder and framc ffor adjusting fsaid tool holder togwardsthelworkiholder, means' for adjusting 'said .toolI vlioldergalong .the work,l :a grinding' 'wheel on said tool holder, said work tablefhavngiarsubstantially horizontal top and side thereofiifacing `towardsthey'grindingwheel, a vertical stationary :viewing;;screen,,a housing fixed to the-"frameiat .theffrearxof'- saidsholders andtextending upwardly .sto point aabove gthe levelof said Yholders and supportingsaid screen .directly above fithe .tool @holder land work #holder and t facing outwardly stowards' the operators'iposition` .'wheni the ioper- :ator is `facing A.the `Awork 'holder and -tool holder, :said: housing :having light reflecting ymeans, and -an.-objective lens for-:producing an enlarged'sur- 4face projection of thextace of the work'on said r.screen,; means forzillu-minating the upperfsurface ofthe work--comprisingz-a `pair of lightsources varranged onsaid'fra-me to direct -beams torsaid ,worksurface which .converge downwardly at substantially equal angles tdaperpendicular from I-the Workxsup-porting surf-ace of the workta-ble :inaplanefwhich istransverseof the work table ,.andsubstantially parallel to the -side 'of' .the work Al`*table facing :towards the grinding l Wheel :and .-means providing'.l anv ,illuminated background on the projection.

. .5.;,In azmachnetooLraziran.1e..;havingaal work holder-..and fa .toolfholden ai; slide-yon .-.whichsone of saidY` .holders ,is ,mounted, a support -ronssad .frame carrying :said slide .-for rectilinear feed .movement respectingtheiother holderfandoper- `ating kpart .telescopically 1associated with :said .slide .and providing .therewith4 a v.fluid chamber .of -adjustable capacity, :a Athreaded interconnection, between, said operating part and saidfframe and :including a feed .screwugproviding a coarse adjustment for positively moving said lpart'xin the direction.. of 'f slide; movement, means yieldingly. urgngssaid -slide.towardssaidL part, control -`means..including;.. a; control Lchamber,.lnayrig .a manually adjustable .control plunger, aa ufluid connection .betweensgsaid .controlmeansgande said .fluid chamber.'..a/gquantityf.of..liquid-pulling said .control ...chamben :fluid :connection tand :..fluid Vjchamber, said fluidfchamber;connectiongandcon- :trol means .providing a liquid '.lleddiuid System .of :constant :capacityv so that" feed -movements of fthe slide Aare iobtaned 44by-.Jadjustment ;ogf said plunger.

E6. Inga grindingrmachine, a iframeqhaving fa work holder and a grinding wheel holder,': a;slide .carrying one; of saidf-holders .for rectilinearfeed movement, .interiitting` piston andcylinder ele- V:ments .i one Afixedv to saidv slide, -a :manuaIIyyadjustable feed screw operably.- interconnectingsaid frame .land the. .other :of said elements, saidselements .providing a i-.iiuid .rchamber .of Nariable capacity, means 'yieldingly purging .zsaid :piston and. cylinder elements :towards collapsed. condition, l.an zadjustable control `chamberhaving means'.accessiblegtothe operatorrfor .-precise::con troliof the size.;of;.said;zcontrol chamber, and-.a fluid connection between 3 said control chamber and fluid chamber, :ava quantity .of .':liquid: lling Jsaid control. chambergiiuid .connection-.and iiuid chamber,l said fluid connectionycontrol .chamber and `'iiuid chamber providingftherewith .,a;.liq\1id filled system offconstantfcapacity.

"7. In Va machine .'tool, .a frame havingA a'wo'rk *holder and agrinding wheel holder, aslidepn which the grinding wheel 4holder is .mountedfa support von'said frame carrying said slide r.for rectilinear feed movement towards and from "the work holder, an. operating part telescopically associated with said slide and .providing therewitha iiuid chamber of :adjustable capacity, a feed screw operably interconnecting: said `,part andv said V`frame and providing e a icoarse adjustmenttfor positively vmoving saidpart in v'direction of slide movement, springmeansyieldingly urging said slideftowardssaidpart and-arranged so that'thespring pressure onthe'slide tends tomove the slide `away from the work holder, control means includingf'a lcontrol chamber having a manually adjustable plunger conveniently controllable from the operators position, a fluid connection `betweenl said control means and -said fluid chamber, a quantity of' liquid fillingsaid 'fluid chamber, control chamber and fluidvconnection, said fluid chamber -andfcontrol means providing -a liquid 'filled system of constant lcapacity -so that feed movements'of the slide=are obtained by adjustment of saidplunger.

8. In a machine toolga frame having `a'fworlr holder and a-tool holder, aiirst slideon which said tool holder is mountedfa second-slide oper- -ablymounted onsaidframe for rectilinearfeed `movement, in one directionfand carrying ysaid-feed slide for-rectilinear feed movement-in-.a-.fsecond direction, an operating part:telescopicallyzasso- 'ciated withi'each :of saidV` slides :and lproviding :ftherewithiuidchambersrof fadjustablegcapacity,

iluid chamber, a quantity of liquid filling said fluid chamber, fluid connection and control chamber, said fluid chamber, connection and control means of each slide providing a liquid filled fluid system of constant capacity so that feed movements of the slides are obtained by adjustment of said plungers.

9. In a grinding machine, a frame havingl a work holder and a grinding wheel holder, a pair of slides carrying one of said holders for rectilinear feed movements in different angularly related directions, and control means providing coarse and fine adjustments for each of said slides, each such control means comprising a feed screw, intertting piston and cylinder Yelements one fixed to a slide and the other manually adjustable by said screw and providing a fluid chamber of variable capacity, means yieldingly urging said piston and cylinder element towards collapsed condition, an adjustable control chamber having a manually operable member for precise control of the size of said control y having a work holder and a tool holder, a slide 4 on which one of said holders is mounted, a support on said frame carrying said slide for rectilinear feed movement respecting the other holder,

10 an operating part telescopically associated with said slide and providing therewith a uid chamber of adjustable capacity, a threaded interconnection between said' operating part and said frame and including a feed screw providing a coarse adjustment for positively moving said part in the direction of slide movement, means yieldingly urging said slide towards said part, control means including telescopic piston and cylinder elements forming a control chamber, a fluid connection between said control chamber and said lluid chamber, a quantity of liquid filling said control chamber, fluid connection and fluid chamber, said control chamber, fluid connection and fluid chamber providing a liquid filled fluid system of constant capacity so that feed movements of the slide take place as the capacity of the control chamber is changed and a manually operable adjusting screw operably engaging one of said elements to change its positionA relatively to the other of'said elements to change the capacity of the control chamber.

LOUIS F. POLK. WILLIS FAY ALLER.

REFERENCES CITED 'Ille following` references are of record in the le of this patent:`

UNITED STATES PATENTS Number Name Date 1,788,475 Van Norman Jan. 13, 1931 1,813,165 Jung July 7, 1931 1,881,984 Van Norman Oct. 11, 1932 2,067,491 Kingsbury Jan. 12, 1937 2,164,169 Wohlfarth June 27, 1939 2,248,446 Wohlfarth July 8, 1941 2,302,572 Reason Nov. 17, 19,42 I 2,384,527 Blesi Sept. 11, 1945 '2,399,907 Blair May 7, 1946 2,404,770 Bennett July 30, 1946 2,406,299 Koulicovitch Aug. 20, 1946 2,481,381 Banko Sept. 6, 1949 FOREIGN PATENTS Number Country n Date Switzerland Sept. 16, 1935 

